Add ArcContainerStopReason.

The enum value will be used in D-Bus signal communication
with Chrome.
Also, it will be used for internal representation of ARC container
stop reason in session_manager.

BUG=b:76152951
TEST=Tested with the depending CLs.

Change-Id: Id537af831447fee1cd85e4781e15558f59cfaa5a
Reviewed-on: https://chromium-review.googlesource.com/998232
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
1 file changed